U.S. patent application number 12/601334 was filed with the patent office on 2010-08-26 for double shock-absorbing steering wheel with epicycloidal gear train.
Invention is credited to Patrick Le Moal.
Application Number | 20100216555 12/601334 |
Document ID | / |
Family ID | 38924831 |
Filed Date | 2010-08-26 |
United States Patent
Application |
20100216555 |
Kind Code |
A1 |
Le Moal; Patrick |
August 26, 2010 |
DOUBLE SHOCK-ABSORBING STEERING WHEEL WITH EPICYCLOIDAL GEAR
TRAIN
Abstract
A double shock-absorbing steering wheel, in particular for
automobile vehicles, including a primary inertia mass connected to
an engine shaft (12), a secondary inertia mass (14) connected by
clutch E to a gearbox BV, and a torsion damper (18) rotatably
connecting the two inertia masses (10, 14). The torsion damper
includes an epicycloidal gear train whose outer crown wheel (22)
engages with a spring (28) for absorption of vibrations and
rotation acyclisms. The spring is mounted around the crown wheel
(22) in a fixed frame (26).
Inventors: |
Le Moal; Patrick; (Amiens,
FR) |
Correspondence
Address: |
BERENATO & WHITE, LLC
6550 ROCK SPRING DRIVE, SUITE 240
BETHESDA
MD
20817
US
|
Family ID: |
38924831 |
Appl. No.: |
12/601334 |
Filed: |
May 22, 2008 |
PCT Filed: |
May 22, 2008 |
PCT NO: |
PCT/FR2008/000707 |
371 Date: |
March 30, 2010 |
Current U.S.
Class: |
464/61.1 |
Current CPC
Class: |
F16H 1/2818 20130101;
F16F 15/13157 20130101; Y10T 74/2131 20150115; Y10T 74/2127
20150115; F16F 15/315 20130101 |
Class at
Publication: |
464/61.1 |
International
Class: |
F16D 3/12 20060101
F16D003/12; F16D 3/64 20060101 F16D003/64; F16F 15/121 20060101
F16F015/121 |
Foreign Application Data
Date |
Code |
Application Number |
May 22, 2007 |
FR |
0755200 |
Claims
1. A double shock-absorbing steering wheel, in particular for
automobile vehicles, including two inertia masses (10, 14)
rotatable about the same axis and connected by a torsion damper
(18) including spring means (28) and an epicyclic gear train
consisting of three elements including a sun wheel (20), an outer
crown wheel (22), and a planet gear carrier (24) the planet gears
(25) of which mesh with the sun wheel (20) and the outer crown
wheel (22), characterized in that the spring means (28) are
disposed in a fixed chassis (26) and associated with a first of the
three elements of the epicyclic gear train.
2. A double shock-absorbing steering wheel according to claim 1,
characterized in that the spring means (28) bear on said first
element (22) and on the fixed chassis (26).
3. A double shock-absorbing steering wheel according to claim 1,
characterized in that the rotation of the first element (22)
relative to the fixed chassis (26) is limited by the spring means
(28).
4. A double shock-absorbing steering wheel according to claim 1,
characterized in that the first element (22) includes a radial lug
(32) on which the spring means (28) bear.
5. A double shock-absorbing steering wheel according to claim 1,
characterized in that the spring means comprise a coil spring (28)
mounted in the fixed chassis (26) around the first element
(22).
6. A double shock-absorbing steering wheel according to claim 5,
characterized in that at rest the coil spring (28) extends over
approximately 360.degree. in the fixed chassis (26).
7. A double shock-absorbing steering wheel according to claim 1,
characterized in that the spring means comprise a plurality of
springs mounted end-to-end in the fixed chassis.
8. A double shock-absorbing steering wheel according to claim 1,
characterized in that one of the inertia masses (10, 14) is
connected to the sun wheel (20), the other inertia mass is
connected to the planet gear carrier (24) of the epicyclic gear
train, and the spring means are around the outer crown wheel
(22).
9. A double shock-absorbing steering wheel according to claim 1,
characterized in that one of the inertia masses (10, 14) is
connected to the sun wheel (20) and the other inertia mass is
connected to the outer crown wheel (22), the planet gear carrier
(24) being retained on a fixed chassis (26) by the spring means
(28).
10. A double shock-absorbing steering wheel according to claim 1,
characterized in that the two stages of planet gears (25, 25') are
mounted on the planet gear carrier (24), the planet gears (25) of
one stage meshing with one of the elements of the epicyclic gear
train and the planet gears (25') of the other stage meshing with
another element of that train.
11. A double shock-absorbing steering wheel according to claim 1,
characterized in that the gears of the epicyclic gear train are
45.degree. bevel gears.
12. A double shock-absorbing steering wheel according to claim 1,
characterized in that a pre-damper (16) is mounted between the
primary inertia mass (10) and the element of the epicyclic gear
train connected to that inertia mass.
13. A double shock-absorbing steering wheel according to claim 1,
characterized in that the angular range of movement of the first
element (22) around the rotation axis is approximately 120.degree.
to either side of a rest position.
14. A double shock-absorbing steering wheel according to claim 1,
characterized in that the epicyclic gear train is housed in a
sealed chamber containing a lubrication fluid or is included at
least partially in an internal combustion engine, the epicyclic
gear train being lubricated by the engine oil.
15. A double shock-absorbing steering wheel according to claim 1,
characterized in that it includes means for immobilizing or
allowing free rotation of the first element (22) of the epicyclic
gear train on passing through a resonant frequency.
16. A double shock-absorbing steering wheel according to claim 1,
characterized in that the torsion damper (18) includes energy
dissipation means consisting of an electro-rheological or
magneto-rheological fluid.
Description
[0001] The invention concerns a double shock-absorbing steering
wheel, in particular for automobile vehicles, including two inertia
masses mobile in rotation about the same axis and connected by a
torsion damper including spring means and an epicyclic gear
train.
[0002] A double shock-absorbing steering wheel of this type is
known already, in particular from the document FR-A-2714131, which
describes a double shock-absorbing steering wheel in which the
torsion damper includes an epicyclic gear train. In one embodiment
described in the above prior art document, the sun gear is driven
in rotation by a first inertia mass fastened to the crankshaft of
an internal combustion engine, the outer crown wheel is fastened to
the second inertia mass, and coil springs are mounted in a chamber
delimited by the first inertia mass between that first inertia mass
and the planet gear carrier, between the first inertia mass and the
outer crown wheel or between the outer crown wheel and the planet
gear carrier.
[0003] One advantage of using an epicyclic gear train in the
torsion damper of a double shock-absorbing steering wheel is the
transmission of torque between the two inertia masses with a
transmission ratio determined by the epicyclic gear train. However,
the embodiments described in the document FR-A-2714131 have the
drawback that the springs of the torsion damper, which are driven
in rotation with the inertia masses and are situated at the
external periphery of those inertia masses, are very sensitive to
centrifugal forces and have a hysteresis that increases when the
rotation speed increases, with risks of blocking and jerky
operation.
[0004] One object of the present invention is to avoid these
drawbacks of the prior art.
[0005] To this end it proposes a double shock-absorbing steering
wheel of the aforementioned type, including two inertia masses
rotatable about the same axis and connected by a torsion damper
including spring means and an epicyclic gear train consisting of
three elements consisting of a sun gear, an outer crown wheel and a
planet gear carrier the planet gears of which mesh with the sun
gear and the outer crown wheel, characterized in that the spring
means are disposed in a fixed chassis and associated with one of
the three elements of the epicyclic gear train.
[0006] An essential advantage of the double shock-absorbing
steering wheel of the invention is that the spring means of the
torsion damper are not driven in rotation with the inertia masses
and are therefore not subjected to centrifugal forces in
operation.
[0007] In this double shock-absorbing steering wheel, the spring
means bear on the one hand on the element of the epicyclic gear
train and on the other hand on the fixed chassis, the rotation of
that element relative to the fixed chassis being limited by the
spring means.
[0008] In a preferred embodiment of the invention, the spring means
comprise a coil spring that is mounted in the fixed chassis around
said element and that at rest extends approximately 360.degree.
around the rotation axis of the inertia masses.
[0009] In this case, the angular range of movement of said element
can reach 120.degree. to either side of a rest position, the
authorized angular range of movement between the two inertia masses
being a function of the transmission ratio of the epicyclic gear
train, for example 80.degree. to either side of a rest position if
the transmission ratio of the epicyclic gear train is 1.5, which
represents a performance very much better than that of current
double shock-absorbing steering wheels.
[0010] In another embodiment of the invention, the spring means of
the torsion damper comprise a plurality of springs mounted
end-to-end in the fixed chassis over an angle of approximately
360.degree..
[0011] The spring or springs of the torsion damper can be curved in
their free state to facilitate mounting them in the fixed
chassis.
[0012] According to another feature of the invention, this double
shock-absorbing steering wheel includes a pre-damper between the
primary inertia mass and the element of the epicyclic gear train
that is connected to the primary inertia mass.
[0013] This feature absorbs and damps vibrations and acyclic
rotation when idling and at very low loads.
[0014] The double shock-absorbing steering wheel of the invention
can be mounted in the conventional way in an automobile vehicle
between the internal combustion engine and a gearbox. It can also
be wholly or partially included in the internal combustion engine,
which has the advantage that the gears of the epicyclic gear train
are lubricated by the engine lubricating oil.
[0015] Another advantage of the double shock-absorbing steering
wheel of the invention is that it eliminates the problem of passing
through the resonant frequency on starting and stopping the engine
by immobilizing the secondary inertia mass relative to the primary
inertia mass, which can be done very simply by immobilizing the
element of the epicyclic gear train on the fixed chassis.
[0016] Alternatively, it is possible to free the element of the
epicyclic gear train completely relative to the fixed chassis so as
in this way to separate totally the secondary inertia mass from the
primary inertia mass and pass without difficulty through the
resonant frequency on starting and stopping the engine.
[0017] The invention will be better understood and other features,
details and advantages of the invention will become more clearly
apparent on reading the following description given with reference
to the appended drawings in which:
[0018] FIG. 1 is a simplified diagrammatic view of a double
shock-absorbing steering wheel of the invention;
[0019] FIG. 2 is a front view of the torsion damper of this double
shock-absorbing steering wheel in a rest position;
[0020] FIGS. 3 and 4 are views similar to FIG. 2 representing the
torsion damper in two different operating positions;
[0021] FIGS. 5 to 9 represent variants of the invention.
[0022] The double shock-absorbing steering wheel represented
diagrammatically in FIG. 1 includes a primary inertia mass 10 fixed
to the end of a drive shaft 12 such as the crankshaft of an
internal combustion engine M and a secondary inertia mass 14 that
is coaxial with the primary inertia mass 10 and is for example
connected by a clutch E to the input shaft of a gearbox BV, the two
inertia masses 10, 14 being connected together in rotation by a
pre-damper 16 and by a torsion damper 18.
[0023] According to the invention, the torsion damper 18 includes
an epicyclic gear train consisting of a sun wheel 20, an outer
crown wheel 22 and a planet gear carrier 24 the planet gears 25 of
which mesh with external teeth on the sun wheel 20 and internal
teeth on the outer crown wheel 22.
[0024] In the FIG. 1 example, the pre-damper 16, which is of a
standard type, is mounted between the primary inertia mass 10 and
the planet gear carrier 24. The shaft of the sun wheel 20 is
fastened to the secondary inertia mass 14, which can be centered
and guided in rotation on the primary inertia mass 10 in the
standard manner. The outer crown wheel 22 is guided in rotation in
a fixed chassis 26 which surrounds the epicyclic gear train.
[0025] In this example, the torsion damper 18 also includes a coil
spring 28 around the outer crown wheel of the epicyclic gear train
that extends approximately 360.degree. around the rotation axis of
the double shock-absorbing steering wheel, this spring 28 being
housed and guided in an annular chamber of the fixed chassis 26,
for example.
[0026] The ends of the spring 28 bear on the one hand on a radial
lug 30 of the fixed chassis 26 and on the other hand on a radial
lug 32 of the outer crown wheel 22, the radial lug 30 of the
chassis 26 extending inward whereas the radial lug 32 of the outer
crown wheel 22 extends outward.
[0027] In a known manner, the radial lug 32 of the outer crown
wheel 22 can extend in a diametral plane of the end turns of the
spring 28, whereas in this case the chassis 26 has two radial lugs
30 on respective opposite sides of the diametral lug 32 of the
outer crown wheel 22, as is often the case in torsion dampers using
circumferential springs.
[0028] The spring 28 of the torsion damper can be curved in the
free state to facilitate fitting it around the outer crown wheel
22. Alternatively, it can be straight in the free state and bent
into a curve in order to fit it around the outer crown wheel
22.
[0029] In another variant, the spring 28 can be replaced by two or
more springs mounted end-to-end, these springs being curved or
straight in the free state.
[0030] The double shock-absorbing steering wheel that has just been
described operates in the following manner:
[0031] When idling and at low loads, vibrations and acyclic
rotation are absorbed and damped by the pre-damper 16, whereas the
spring 28 of the torsion damper 18 remains in the state represented
in FIG. 2, where it extends approximately 360.degree. around the
outer crown wheel 22, its two ends bearing on the radial lug 30 of
the fixed chassis and on the radial lug 32 of the outer crown wheel
22.
[0032] When the torque transmitted by the double shock-absorbing
steering wheel increases, vibration and acyclic rotation
transmitted by the drive shaft 12 to the primary inertia mass 10
are absorbed by the spring 28, which is compressed either in the
forward direction as represented in FIG. 3 or in the opposite
direction as represented in FIG. 4, the vibrations and acyclic
rotations being damped by friction means mounted in the standard
manner in the torsion damper 18 between the two inertia masses,
these friction means being well known to the person skilled in the
art and not being represented in the drawings for reasons of
clarity.
[0033] In FIGS. 3 and 4, the spring 28 is in a maximally compressed
state, its turns being contiguous or substantially contiguous.
[0034] In this state, the rotation of the outer crown wheel 22
relative to the fixed chassis 26 is approximately 120.degree., for
example. The corresponding rotation of the secondary inertia mass
relative to the primary inertia mass is determined by the
transmission ratio of the epicyclic gear train. If this ratio is
1.5, for example (which means that the rotation speed of the
secondary inertia mass 14 is 1.5 times the rotation speed of the
primary inertia mass 10), the maximum possible angular range of
movement of the secondary inertia mass 14 relative to the primary
inertia mass 10 is 80.degree. to either side of a median position
if the angular range of movement of the outer crown wheel 22
relative to the fixed chassis is 120.degree. to either side of a
median position. The resulting vibration damping performance is
very much better than that of a standard double shock-absorbing
steering wheel.
[0035] Passage through the resonant frequency, which is a problem
encountered in all double shock-absorbing steering wheels when
stopping and starting the engine of the vehicle, can be solved very
simply in the double shock-absorbing steering wheel of the
invention, either by preventing rotation of the outer crown wheel
22 or by releasing the outer crown wheel, the secondary inertia
mass being then either prevented from rotating relative to the
primary inertia mass or free to rotate relative to that primary
inertia mass on passing through the resonant frequency.
[0036] The outer crown wheel 22 can be immobilized by immobilizing
its radial lug 32 or by application of a brake shoe to the outer
crown wheel. Releasing it so that it can rotate is simply achieved
by retracting the radial lug 30 of the fixed chassis on passing
through the resonant frequency.
[0037] When the double shock-absorbing steering wheel of the
invention is mounted in the standard way in an automobile vehicle
between the engine and the gearbox, the epicyclic gear train of the
torsion damper must be accommodated in a sealed chamber containing
a lubricating liquid.
[0038] If the double shock-absorbing steering wheel of the
invention is included fully or at least partially in the internal
combustion engine of the vehicle, the sealed chamber is no longer
necessary and the components of the epicyclic gear train are
lubricated directly by the engine oil.
[0039] An electro-rheological or magneto-rheological fluid can also
be used as an energy dissipating element in the double
shock-absorbing steering wheel of the invention, these fluids
consisting of suspensions of solid particles the mechanical
properties of which can be adjusted by an external electric or
magnetic field.
[0040] In the FIG. 5 variant, the primary inertia mass 10 is
constrained to rotate with the outer crown wheel 22 and the planet
gear carrier 24 is retained by the spring means 28 housed in a
chamber of a fixed element 26.
[0041] This embodiment differs from that of FIG. 1 in that the
connections of the primary mass 10 and the chassis to the planet
gear carrier and to the outer crown wheel are reversed, the
secondary inertia mass 14 remaining connected to the sun wheel
20.
[0042] FIG. 6 shows the FIG. 5 embodiment to which has been added a
second stage of planet gears 25'. The planet gears 25 of the first
stage mesh with the outer crown wheel 22 and the planet gears 25'
mesh with the sun wheel 20, the planet gears 25 and 25' being
mounted on the same support 24.
[0043] These two stages of planet gears offer greater freedom in
the choice of the transmission ratio of the epicyclic gear train
for a small overall size in the radial direction. The input and
output rotation directions of the epicyclic gear train are
reversed.
[0044] FIG. 7 shows the device from FIG. 6 with a modification of
the contacts of the outer crown wheel 22 and the planet gears 25
from the outside to the inside of the planet gears. This
arrangement has the advantage that the input and output rotation
directions of the epicyclic gear train are the same.
[0045] The device represented in FIG. 8 is that from FIG. 1 with
the addition of a second stage of planet gears 25' as in FIG. 6.
The input and output rotation directions of the gear train are
identical. There is a wider choice of transmission ratios of the
gear train for a small overall size in the radial direction.
[0046] The FIG. 9 variant features the arrangement from FIG. 5 with
45.degree. bevel gears of the type used in a gearbox differential.
The transmission ratio of the gear train is equal to 1, the input
and output rotation directions are reversed, and the overall size
is minimal.
[0047] In all the embodiments represented in the drawings, the
inertia masses are interchangeable, i.e. the primary inertia mass
10 can be connected to the sun wheel 20 and the secondary inertia
mass 14 can be connected to the outer crown wheel 22 or to the
planet gear carrier 24.
* * * * *